Synthesis method and application of a dibenzo-alpha-pyrone compound

Abstract

The application relates to the technical field of organic synthesis, in particular to a synthesis method of a dibenzo-alpha-pyrone compound and application thereof. The synthesis method comprises the following steps: taking a diphenylpropanone compound as a raw material, using an oxidant, a Lewis acid and an oxidation catalyst, and reacting under the condition of an organic solvent and room temperature. The synthesis method takes an easily obtained benzophenone compound as a raw material, prepares the dibenzo-alpha-pyrone compound through one-pot method via Baeyer-Villiger oxidation and Scholl oxidation coupling, the reaction is simple, the condition is mild, and the synthesis method provides a more efficient and green method for preparing bioactive substances such as urolithin a-c.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, and in particular to a method for synthesizing dibenzo-α-pyranone compounds and their applications. Background Technology

[0002] Dibenzo-α-pyranone compounds are an important class of natural metabolites derived from fungi, plants, and animal feces. These compounds exhibit a variety of biological activities, including anti-tumor proliferation, antioxidant, anti-inflammatory, antibacterial, and anti-aging effects. For example, urotarate A, produced from ellagic acid and ellagitannins in plants via the polyketide metabolic pathway in gut microbiota, significantly enhances mitophagy, promotes the clearance of defective mitochondria, improves mitochondrial quality, and reduces oxidative stress, thereby slowing healthy aging and improving Alzheimer's disease. Current methods for synthesizing dibenzo-α-pyranone structures include pathways 1-5, mainly including palladium / copper catalyzed tandem coupling, palladium-catalyzed hydrocarbon activation, diphenyl ester coupling, diphenyl oxidation, and 6H-benzochromene oxidation.

[0003] .

[0004] The above-mentioned synthetic methods have drawbacks such as the use of toxic and expensive reagents, high temperature conditions, long reaction time, and long steps, which have brought difficulties to the synthesis of dibenzo-α-pyranone compounds. Therefore, it is necessary to provide an environmentally friendly, simple and mild method for the synthesis of dibenzo-α-pyranone compounds. Summary of the Invention

[0005] This invention provides a method for synthesizing dibenzo-α-pyranone compounds and its application, which solves the problems of existing synthesis methods such as being environmentally unfriendly, having complicated steps, requiring high reaction conditions, and having long reaction times.

[0006] According to a first aspect of the present invention, the present invention provides a method for synthesizing dibenzo-α-pyranone compounds, comprising the following steps: using a dibenzophenone compound as a raw material, and reacting it with an oxidant, a Lewis acid and an oxidation catalyst in an organic solvent and at room temperature.

[0007] It should be noted that room temperature generally refers to 20-25℃.

[0008] The reaction mechanism of the synthetic method for dibenzo-α-pyranone compounds of this invention is as follows: Benzophenone compounds first undergo a Baeyer-Villiger oxidation reaction under the action of an oxidant to obtain a phenyl benzoate intermediate. Then, the phenyl benzoate intermediate undergoes intramolecular Scholl oxidative coupling under the action of a Lewis acid and an oxidizing catalyst to obtain dibenzo-α-pyranone compounds. The benzophenone compounds used in the synthetic method of this invention are readily available. Based on the principles of Baeyer-Villiger oxidation and Scholl oxidative coupling, a one-pot method for preparing dibenzo-α-pyranone compounds is used. The reaction is simple and the conditions are mild, providing a more efficient and green method for the preparation of bioactive substances such as urolithin (ac). The yield of dibenzo-α-pyranone compounds obtained using the synthetic method of this invention can reach 76%.

[0009] In some specific embodiments, the dibenzo-α-pyranone compounds have structures as shown in formulas I-VIII:

[0010] .

[0011] Furthermore, the benzophenone compounds have a structure as shown in Formula MI: MI, wherein R1, R2, R3, and R4 are each independently selected from H, halogen, alkyl, or alkoxy. Preferably, R1, R2, R3, and R4 are each independently selected from H, halogen, C1-C6 alkyl, or C1-C6 alkoxy; more preferably, R1, R2, R3, and R4 are each independently selected from H, halogen, C1-C3 alkyl, or C1-C3 alkoxy.

[0012] In some specific embodiments, the structure shown by formula MI includes the following formulas MI-1 to MI-7:

[0013] .

[0014] Furthermore, the oxidant is one of m-chloroperoxybenzoic acid, hydrogen peroxide, or tert-butylhydrogen peroxide. These oxidants can carry out oxidation reactions efficiently at room temperature without the need for high temperature or high pressure conditions, greatly reducing energy consumption. These oxidants exhibit high selectivity in the Baeyer-Villiger oxidation reaction, efficiently converting ketone groups to ester groups. In addition, these three oxidants have lower toxicity compared to traditional oxidants (such as chromates or halogens), conforming to the principles of green chemistry, making the entire synthesis process more environmentally friendly and reducing pollution.

[0015] To improve reaction efficiency, the molar amount of the oxidant is further 1-10 times the molar amount of the benzophenone compound. Optionally, the molar amount of the oxidant can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 times the molar amount of the benzophenone compound, or other values ​​within the above range, which are not limited here.

[0016] Preferably, the molar amount of the oxidant is 1-2 times the molar amount of the benzophenone compound. By optimizing the molar amount of the oxidant, it is ensured that the ketone group in the substrate undergoes sufficient Baeyer-Villiger oxidation to generate enough ester intermediates. Too little oxidant may lead to incomplete reaction, while too much oxidant may lead to over-oxidation, generating unnecessary byproducts. Controlling the amount of oxidant within the range of 1-2 times ensures both complete reaction and avoids over-oxidation, thereby improving the selectivity and yield of the target product.

[0017] Furthermore, the Lewis acid is one of zinc sulfide, aluminum trichloride, or ferric bromide. These Lewis acids can promote the reaction at room temperature or lower temperatures, avoiding the energy consumption and side reaction problems caused by high-temperature conditions. Zinc sulfide, aluminum trichloride, and ferric bromide, as Lewis acids, can effectively activate the reaction substrate, accelerate the Baeyer-Villiger oxidation and Scholl coupling reactions, and improve the reaction rate and yield.

[0018] To improve reaction efficiency, the molar amount of the Lewis acid is further 0.05-0.5 times the molar amount of the benzophenone compound. Optionally, the molar amount of the Lewis acid relative to the molar amount of the benzophenone compound can be 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, or 0.5 times, or other values ​​within the above range, and is not limited here.

[0019] Preferably, the molar amount of the Lewis acid is 0.1-0.3 times the molar amount of the benzophenone compound. Experiments show that the Lewis acid can efficiently promote the reaction within the range of 0.1-0.3 times the molar amount. This range ensures catalytic activity while avoiding side reactions or an overly complex reaction system caused by excessive Lewis acid. Too little Lewis acid may result in an incomplete reaction, while excessive Lewis acid may lead to various side reactions, reducing the selectivity and yield of the target product. By controlling the amount within an appropriate range, side reactions can be significantly reduced, and the purity and yield of the target product can be improved.

[0020] Furthermore, the oxidation catalyst is ferric porphyrin chloride. Ferric porphyrin chloride catalysts can efficiently promote the Baeyer-Villiger oxidation reaction and the Scholl oxidative coupling reaction, which are key steps in the synthesis of the dibenzo-α-pyranone skeleton structure. They exhibit high catalytic activity, enabling rapid initiation of the reaction under mild conditions and significantly increasing the reaction rate. Ferric porphyrin chloride can catalyze the reaction at or near room temperature, eliminating the need for harsh conditions such as high temperature and high pressure. This not only reduces energy consumption but also minimizes the occurrence of side reactions.

[0021] Preferably, the oxidation catalyst is one of ferric porphyrin (CAS No.: 16009-13-5), 5,10,15,20-tetraphenyl-21H,23H-porphyrin ferric chloride (III) (CAS No.: 16456-81-8), or meso-tetra(4-carboxyphenyl)porphyrin ferric chloride (CAS No.: 55266-17-6). By selecting different ferric porphyrins, the reaction conditions can be further optimized to achieve selective synthesis of different products.

[0022] To further improve the reaction efficiency, the molar amount of the oxidation catalyst is 0.05-0.5 times the molar amount of the benzophenone compound. Optionally, the molar amount of the oxidation catalyst can be 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, or 0.5 times, or other values ​​within the above range, and is not limited here.

[0023] Preferably, the molar amount of the oxidation catalyst is 0.08-0.15 times the molar amount of the benzophenone compound. Experiments show that a dosage range of 0.08-0.15 times ensures that the catalyst plays a full role in the reaction, effectively promoting the Baeyer-Villiger oxidation and Scholl coupling reaction, thereby guaranteeing a high reaction rate and high yield. Too low a dosage may lead to a decrease in reaction rate and yield; while too high a dosage may lead to an increase in side reactions and a decrease in product purity.

[0024] Furthermore, the organic solvent is tetrahydrofuran, dichloromethane, or hexafluoroisopropyl ether. Different solvents have different physicochemical properties (such as polarity, solubility, volatility, etc.). Selecting a suitable solvent based on the specific reaction conditions and substrate characteristics can improve reaction efficiency and product yield. Experiments have shown that tetrahydrofuran, dichloromethane, or hexafluoroisopropyl ether all exhibit good reactivity.

[0025] Preferably, the organic solvent is hexafluoroisopropyl ether. Hexafluoroisopropyl ether is a solvent with excellent dissolving power, capable of effectively dissolving benzophenone substrates, catalysts, and oxidants in the reaction, ensuring the homogeneity of the reaction system and thus improving reaction efficiency. Hexafluoroisopropyl ether has a low boiling point (approximately 55-60°C), and the solvent can be quickly removed by simple rotary evaporation after the reaction, simplifying post-processing steps and reducing energy consumption. Compared with traditional organic solvents (such as dichloromethane), hexafluoroisopropyl ether is less toxic and poses less harm to operators and the environment, meeting the requirements of green chemistry. Experiments have shown that hexafluoroisopropyl ether exhibits higher reaction efficiency and product purity compared to tetrahydrofuran and dichloromethane.

[0026] Furthermore, the reaction time is 12-48 hours. This 12-48 hour time range ensures that the reaction proceeds fully, allowing the reactants to be completely converted into the target product. It avoids incomplete conversion due to too short a reaction time or the formation of byproducts due to too long a reaction time, thereby improving the purity of the target product.

[0027] Furthermore, the process includes the following steps: washing, concentrating, and purifying the reactants. The washing step effectively removes water-soluble impurities or unreacted raw materials generated during the reaction, reducing the impact of impurities on subsequent steps. Concentration and purification steps (such as column chromatography and recrystallization) further separate and remove byproducts, ensuring the high purity of the target product.

[0028] In some specific embodiments, the washing, concentration, and purification of the reaction materials specifically involves adding distilled water to the reaction solution after the reaction is completed, then extracting with dichloromethane, combining the organic phases, concentrating with a rotary evaporator, and purifying the residue by silica gel column chromatography.

[0029] According to a second aspect of the present invention, the present invention also provides the application of the above-described synthesis method in the synthesis of urolithin, wherein the application method is as follows: a dibenzo-α-pyranone compound is synthesized using the above-described synthesis method, and then urolithin is obtained by dealkylation reaction using the synthesized dibenzo-α-pyranone compound as a raw material.

[0030] Furthermore, the dealkylation reaction is carried out via boron tribromide demethylation.

[0031] It should be noted that urolithin includes urolithin a, urolithin b, and urolithin c, and their structural formulas are as follows:

[0032] .

[0033] In some specific embodiments, the synthesis method of urolithin is as follows: At room temperature, a dibenzo-α-pyranone compound is dissolved in an organic solvent (e.g., dichloromethane), and then a dichloromethane solution of boron tribromide is added and reacted for 10-15 hours. After the reaction is complete, a saturated sodium bicarbonate solution is added to the reaction solution, followed by extraction with dichloromethane. The organic phases are combined, concentrated using a rotary evaporator, and the residue is purified by silica gel column chromatography.

[0034] The beneficial effects of this invention are:

[0035] This invention provides a method for synthesizing dibenzo-α-pyranone compounds using readily available benzophenone compounds as raw materials. The method involves a one-pot process via Baeyer-Villiger oxidation and Scholl oxidation coupling to prepare dibenzo-α-pyranone compounds. The reaction is simple and the conditions are mild, providing a more efficient and green method for the preparation of bioactive substances such as urolithin (ac). Attached Figure Description

[0036] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 This is the 1H NMR spectrum of the dibenzo-α-pyranone compound provided in Example 1 of this invention.

[0038] Figure 2 This is the carbon NMR spectrum of the dibenzo-α-pyranone compound provided in Example 1 of this invention.

[0039] Figure 3 This is the 1H NMR spectrum of the dibenzo-α-pyranone compound of Formula I obtained in Example 16 of this invention.

[0040] Figure 4 This is the carbon NMR spectrum of the dibenzo-α-pyranone compound of formula I obtained in Example 16 of this invention.

[0041] Figure 5 This is the 1H NMR spectrum of the dibenzo-α-pyranone compound of formula VIII obtained in Example 16 of this invention.

[0042] Figure 6 This is the carbon NMR spectrum of the dibenzo-α-pyranone compound of formula VIII obtained in Example 16 of this invention.

[0043] Figure 7This is the 1H NMR spectrum of the dibenzo-α-pyranone compound of formula II obtained in Example 17 of this invention.

[0044] Figure 8 This is the carbon NMR spectrum of the dibenzo-α-pyranone compound of formula II obtained in Example 17 of this invention.

[0045] Figure 9 This is the 1H NMR spectrum of the dibenzo-α-pyranone compound of formula IV obtained in Example 18 of this invention.

[0046] Figure 10 This is the carbon NMR spectrum of the dibenzo-α-pyranone compound of formula IV obtained in Example 18 of this invention.

[0047] Figure 11 This is the 1H NMR spectrum of the dibenzo-α-pyranone compound of formula V obtained in Example 19 of this invention.

[0048] Figure 12 This is the carbon NMR spectrum of the dibenzo-α-pyranone compound of formula V obtained in Example 19 of this invention.

[0049] Figure 13 This is the 1H NMR spectrum of the dibenzo-α-pyranone compound of formula VI obtained in Example 20 of this invention.

[0050] Figure 14 This is the carbon NMR spectrum of the dibenzo-α-pyranone compound of formula VI obtained in Example 20 of this invention.

[0051] Figure 15 This is the 1H NMR spectrum of the dibenzo-α-pyranone compound of formula VII obtained in Example 21 of this invention.

[0052] Figure 16 This is the carbon NMR spectrum of the dibenzo-α-pyranone compound of formula VII obtained in Example 21 of this invention.

[0053] Figure 17 This is the 1H NMR spectrum of urolithin a obtained in Example 22 of this invention.

[0054] Figure 18 This is the carbon NMR spectrum of urolithin a obtained in Example 22 of the present invention.

[0055] Figure 19 This is the 1H NMR spectrum of urolithin b obtained in Example 23 of this invention.

[0056] Figure 20 This is the carbon NMR spectrum of urolithin b obtained in Example 23 of the present invention.

[0057] Figure 21This is the 1H NMR spectrum of urolithin c obtained in Example 24 of this invention.

[0058] Figure 22 This is the carbon NMR spectrum of urolithin c obtained in Example 24 of this invention. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0060] The structural formulas of the dibenzo-α-pyranone compounds involved in the following examples are shown in Formulas I-VIII:

[0061] .

[0062] Example 1

[0063] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0064] At room temperature, substituted 3,3'-dimethoxybenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.4 mmol), FeTCPP (0.04 mmol), and zinc sulfide (0.08 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 42.5 mg of the target product, with a yield of 42%.

[0065] like Figure 1 As shown, the 1H NMR data of the dibenzo-α-pyranone compounds of formula III are as follows:

[0066] 1H NMR (600 MHz, CDCl3) δ 7.93 (d, J = 8.9 Hz, 1H), 7.87 (d, J = 8.8Hz, 1H), 7.77 (d, J = 2.8 Hz, 1H), 7.38 (dd, J = 8.8, 2.8 Hz, 1H), 6.91 (dd,J = 8.8, 2.6 Hz, 1H), 6.87 (d, J = 2.5 Hz, 1H), 3.93 (s, 3H), 3.88 (s, 3H).

[0067] like Figure 2 As shown, the carbon NMR data for formula III are as follows:

[0068] 13 C NMR (151 MHz, CDCl3) δ 161.83, 160.84, 159.33, 151.82, 128.86,124.71, 123.33, 123.01, 121.15, 112.59, 111.48, 111.12, 101.72, 55.94, 55.86.

[0069] The high-resolution mass spectrometry data of the dibenzo-α-pyranone compounds of formula III are as follows: HRMS (ESI): m / z calcd. C 15 H 13 O4 [M+H] + : 257.0828, found 257.0814.

[0070] Example 2

[0071] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0072] At room temperature, substituted 3,3'-dimethoxybenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.6 mmol), FeTCPP (0.04 mmol), and zinc sulfide (0.08 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 75 mg of the target product, with a yield of 76%.

[0073] Example 3

[0074] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0075] At room temperature, substituted 3,3'-dimethoxybenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.8 mmol), FeTCPP (0.04 mmol), and zinc sulfide (0.08 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 75 mg of the target product, with a yield of 76%.

[0076] Example 4

[0077] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0078] At room temperature, substituted 3,3'-dimethoxybenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (1.6 mmol), FeTCPP (0.04 mmol), and zinc sulfide (0.08 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 63.1 mg of the target product, with a yield of 64%.

[0079] Example 5

[0080] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0081] At room temperature, substituted 3,3'-dimethoxybenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (4 mmol), FeTCPP (0.04 mmol), and zinc sulfide (0.08 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 25.6 mg of the target product, with a yield of 26%.

[0082] Example 6

[0083] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0084] At room temperature, substituted 3,3'-dimethoxybenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.6 mmol), FeTCPP (0.02 mmol), and zinc sulfide (0.08 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 75 mg of the target product, with a yield of 76%.

[0085] Example 7

[0086] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0087] At room temperature, substituted 3,3'-dimethoxybenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.6 mmol), FeTCPP (0.08 mmol), and zinc sulfide (0.08 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 75 mg of the target product, with a yield of 76%.

[0088] Example 8

[0089] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0090] At room temperature, substituted 3,3'-dimethoxybenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.6 mmol), FeTCPP (0.2 mmol), and zinc sulfide (0.08 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 75 mg of the target product, with a yield of 76%.

[0091] Example 9

[0092] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0093] At room temperature, substituted 3,3'-dimethoxybenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.6 mmol), FeTCPP (0.04 mmol), and zinc sulfide (0.02 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 12.8 mg of the target product, with a yield of 13%.

[0094] Example 10

[0095] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0096] At room temperature, substituted 3,3'-dimethoxybenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.6 mmol), FeTCPP (0.04 mmol), and zinc sulfide (0.04 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 56.2 mg of the target product, with a yield of 57%.

[0097] Example 11

[0098] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0099] At room temperature, substituted 3,3'-dimethoxybenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.6 mmol), FeTCPP (0.04 mmol), and zinc sulfide (0.2 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 34.5 mg of the target product, with a yield of 35%.

[0100] Example 12

[0101] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0102] At room temperature, substituted 3,3'-dimethoxybenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.4 mmol), FeTCPP (0.04 mmol), and zinc sulfide (0.08 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of tetrahydrofuran. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 42.5 mg of the target product, with a yield of 42%.

[0103] Example 13

[0104] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0105] At room temperature, substituted 3,3'-dimethoxybenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.4 mmol), FeTCPP (0.04 mmol), and zinc sulfide (0.08 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of dichloromethane. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 33.5 mg of the target product, with a yield of 34%.

[0106] Example 14

[0107] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0108] At room temperature, substituted 3,3'-dimethoxybenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.4 mmol), FeTCPP (0.04 mmol), and zinc sulfide (0.08 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 12 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 26.4 mg of the target product, with a yield of 25%.

[0109] Example 15

[0110] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0111] At room temperature, substituted 3,3'-dimethoxybenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.4 mmol), FeTCPP (0.04 mmol), and zinc sulfide (0.08 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 48 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 32.7 mg of the target product, with a yield of 32%.

[0112] Example 16

[0113] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0114] At room temperature, substituted 3-methoxybenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.6 mmol), FeTCPP (0.04 mmol), and zinc sulfide (0.08 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to obtain 31 mg of the target product of formula I and 25.4 mg of formula VIII, with yields of 37.5% and 30%, respectively.

[0115] like Figure 3 As shown, the 1H NMR spectrum data of Formula I are as follows:

[0116] 1 H NMR (600 MHz, CDCl3) δ 8.39 (dd, J = 8.0, 1.0 Hz, 1H), 8.03 (d, J =8.1 Hz, 1H), 7.98 (d, J = 8.8 Hz, 1H), 7.833 - 7.80 (m, 1H), 7.56 - 7.52 (m,1H), 6.95 (dd, J = 8.8, 2.6 Hz, 1H), 6.90 (d, J = 2.5 Hz, 1H), 3.92 (s, 3H).

[0117] like Figure 4 As shown, the carbon NMR data for formula I are as follows:

[0118] 13 C NMR (151 MHz, CDCl3) δ 161.70, 161.64, 152.78, 135.34, 135.05,130.74, 127.91, 123.95, 121.25, 120.13, 112.64, 111.31, 101.77, 55.88.

[0119] The high-resolution mass spectrometry data obtained for Equation I are: HRMS (ESI): m / z calcd. C 13 H9O3 [M+H] + :213.0552, found 213.0524.

[0120] like Figure 5 As shown, the 1H NMR spectrum data of formula VIII are as follows:

[0121] 1 H NMR (600 MHz, CDCl3) δ 8.05 (d, J = 8.8 Hz, 1H), 8.00 (dd, J = 7.9,1.4 Hz, 1H), 7.82 (d, J = 2.8 Hz, 1H), 7.43 (ddd, J = 8.5, 7.2, 1.5 Hz, 1H), 7.41 (dd, J = 8.8, 2.8 Hz, 1H), 7.37 (dd, J = 8.2, 1.1 Hz, 1H), 7.34 - 7.32(m, 1H), 3.94 (s, 3H).

[0122] like Figure 6 As shown, the carbon NMR data for formula VIII are as follows:

[0123] 13 C NMR (151 MHz, CDCl3) δ 161.37, 160.04, 150.45, 129.38, 128.17,124.61, 124.37, 123.49, 122.44, 122.23, 118.20, 117.64, 111.15, 55.84.

[0124] The high-resolution mass spectrometry data for Formula VIII are as follows: HRMS (ESI): m / z calcd. C 13 H9O3 [M+H] + :213.0552, found 213.0558.

[0125] Example 17

[0126] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0127] At room temperature, substituted 3,4,3'-trimethoxybenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.6 mmol), FeTCPP (0.04 mmol), and zinc sulfide (0.08 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 158 mg of the target product, formula II, in 62% yield.

[0128] like Figure 7 As shown, the 1H NMR spectrum data of Formula II are as follows:

[0129] 1 H NMR (600 MHz, CDCl3) δ 8.40 (dd, J = 7.9, 1.1 Hz, 1H), 8.00 (d, J =8.1 Hz, 1H), 7.84 - 7.81 (m, 1H), 7.56 - 7.53 (m, 1H), 7.43 (s, 1H), 6.91 (s,1H), 4.03 (s, 3H), 3.98 (s, 3H).

[0130] like Figure 8 As shown, the carbon NMR data for formula II are as follows:

[0131] 13 C NMR (151 MHz, CDCl3) δ 161.80, 151.56, 146.61, 146.53, 135.29,134.94, 130.85, 127.93, 121.21, 120.38, 110.15, 104.01, 100.98, 56.61, 56.45.

[0132] The high-resolution mass spectrometry data obtained for Equation II are: HRMS (ESI): m / z calcd. C 16 H 15 O5 [M+H] + :287.0926, found 287.0919.

[0133] Example 18

[0134] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0135] At room temperature, substituted 3-methoxy-4'-chlorobenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.6 mmol), FeTCPP (0.04 mmol), and zinc sulfide (0.08 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 64 mg of the target product, formula IV, in 61.2% yield.

[0136] like Figure 9 As shown, the 1H NMR spectrum data of formula IV are as follows:

[0137] 1 H NMR (600 MHz, CDCl3) δ 7.98 (d, J = 8.8 Hz, 1H), 7.94 (d, J = 2.3Hz, 1H), 7.81 (d, J = 2.8 Hz, 1H), 7.41 (dd, J = 8.8, 2.8 Hz, 1H), 7.37 (dd,J = 8.7, 2.4 Hz, 1H), 7.30 (d, J = 8.7 Hz, 1H), 3.92 (s, 3H).

[0138] like Figure 10 As shown, the carbon NMR data of formula IV are as follows:

[0139] 13 C NMR (151 MHz, CDCl3) δ 160.93, 160.71, 148.95, 130.21, 129.38,127.03, 124.58, 123.76, 122.68, 122.21, 119.71, 119.16, 111.57, 56.04.

[0140] The high-resolution mass spectrometry data of Formula IV obtained are as follows: HRMS (ESI): m / z calcd. C 14 H 10 ClO3 [M+H] + :261.0328, found 261.0318.

[0141] Example 19

[0142] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0143] At room temperature, substituted 3,4-dimethoxybenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.6 mmol), FeTCPP (0.04 mmol), and zinc sulfide (0.08 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 71 mg of the target product, formula V, in 69.5% yield.

[0144] like Figure 11 As shown, the 1H NMR spectrum data of the obtained formula V are as follows:

[0145] 1 H NMR (600 MHz, CDCl3) δ 8.40 (dd, J = 7.9, 1.1 Hz, 1H), 8.00 (d, J =8.1 Hz, 1H), 7.84 - 7.81 (m, 1H), 7.56 - 7.53 (m, 1H), 7.43 (s, 1H), 6.91 (s,1H), 4.03 (s, 3H), 3.98 (s, 3H).

[0146] like Figure 12 As shown, the carbon NMR data of the obtained formula V are as follows:

[0147] 13 C NMR (151 MHz, CDCl3) δ 161.80, 151.56, 146.61, 146.53, 135.29,134.94, 130.85, 127.93, 121.21, 120.38, 110.15, 104.01, 100.98, 56.61, 56.45.

[0148] The high-resolution mass spectrometry data of formula V are as follows: HRMS (ESI): m / z calcd. C 15 H 13 O4 [M+H] + :257.0842, found 257.0814.

[0149] Example 20

[0150] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0151] At room temperature, substituted 4-chlorobenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.6 mmol), FeTCPP (0.04 mmol), and zinc sulfide (0.08 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 71 mg of the target product, formula VI, in 77.5% yield.

[0152] like Figure 13 As shown, the 1H NMR spectrum data of the obtained formula VI are as follows:

[0153] 1 H NMR (600 MHz, CDCl3) δ 8.41 (dd, J = 7.9, 1.0 Hz, 1H), 8.06 (d, J =8.1 Hz, 1H), 8.02 (d, J = 2.4 Hz, 1H), 7.87 - 7.85 (m, 1H), 7.65 - 7.63 (m,1H), 7.43 (dd, J = 8.8, 2.4 Hz, 1H), 7.32 (d, J = 8.7 Hz, 1H).

[0154] like Figure 14 As shown, the carbon NMR data of the obtained formula VI are as follows:

[0155] 13 C NMR (151 MHz, CDCl3) δ 160.78, 149.82, 135.25, 133.73, 130.90,130.53, 130.21, 129.79, 122.78, 121.96, 121.38, 119.52, 119.37.

[0156] The high-resolution mass spectrometry data for Equation VI are as follows: HRMS (ESI): m / z calcd. C 15 H 13 O4 [M+H] + :231.0235, found 231.0213.

[0157] Example 21

[0158] This embodiment provides a method for synthesizing dibenzo-α-pyranone compounds, specifically including the following steps:

[0159] At room temperature, substituted 3-methylbenzophenone (0.4 mmol), m-chloroperoxybenzoic acid (0.6 mmol), FeTCPP (0.04 mmol), and zinc sulfide (0.08 mmol) were added sequentially to a 25 mL reaction flask equipped with a magnetic stirrer, followed by the addition of 2 mL of hexafluoroisopropyl ether. The reaction was carried out at room temperature for 24 hours. After the reaction was completed, 5 mL of distilled water was added to the reaction solution, followed by extraction with dichloromethane (5 mL x 3 times). The organic phases were combined, concentrated using a rotary evaporator, and the residue was purified by silica gel column chromatography to give 50 mg of the target product, formula VII, in 59.6% yield.

[0160] like Figure 15 As shown, the 1H NMR spectrum data of the obtained formula VII are as follows:

[0161] 1 H NMR (600 MHz, CDCl3) δ 8.22 (d, J = 0.4 Hz, 1H), 8.05 (dd, J =12.7, 4.8 Hz, 2H), 7.67 - 7.64 (m, 1H), 7.48 - 7.45 (m, 1H), 7.37 (dd, J =8.2, 1.1 Hz, 1H), 7.33 (ddd, J = 31.5, 18.3, 14.3 Hz, 1H), 2.51 (s, 3H).

[0162] like Figure 16 As shown, the carbon NMR data for equation VII are as follows:

[0163] 13 C NMR (151 MHz, CDCl3) δ 161.63, 151.18, 139.44, 136.28, 132.42,130.59, 130.11, 124.67, 122.72, 121.88, 121.26, 118.39, 117.90, 21.51.

[0164] The high-resolution mass spectrometry data obtained for Equation VII are: HRMS (ESI): m / z calcd. C 15 H 13 O4 [M+H] + :211.0755, found 211.0759.

[0165] Example 22

[0166] This embodiment provides a method for synthesizing urolithin a, which specifically includes the following steps:

[0167] At room temperature, a dibenzo-α-pyranone compound of formula III (2 mmol) was added to a 25 mL reaction flask equipped with a magnetic stirrer and dissolved in 10 mL of dichloromethane. Then, 3 mL of a 1 mol / L dichloromethane solution of boron tribromide was added, and the reaction was carried out at room temperature for 12 hours. After the reaction was completed, 10 mL of saturated sodium bicarbonate solution was added to the reaction solution, followed by extraction with dichloromethane (10 mL * 3 times). The organic phases were combined, concentrated by rotary evaporator, and the residue was purified by silica gel column chromatography to give 300 mg of urolithin a, with a yield of 68%.

[0168] like Figure 17 As shown, the obtained 1H NMR spectrum data of urolithin a are as follows:

[0169] 1 H NMR (600 MHz, DMSO) δ 10.23 (s, 2H), 8.08 (d, J = 8.8 Hz, 1H), 7.99 (d, J = 8.8 Hz, 1H), 7.51 (d, J = 2.7 Hz, 1H), 7.30 (dd, J = 8.7, 2.7Hz, 1H), 6.80 (dd, J = 8.7, 2.4 Hz, 1H), 6.72 (d, J = 2.4 Hz, 1H).

[0170] like Figure 18 As shown, the obtained carbon NMR data for urolithin a are as follows:

[0171] 13 C NMR (151 MHz, DMSO) δ 160.72, 158.66, 157.06, 150.98, 127.01,124.24, 123.86, 123.63, 120.24, 113.61, 113.11, 109.90, 102.94.

[0172] The obtained high-resolution mass spectrometry data of urolithin a are: HRMS (ESI): m / z calcd. C 13 H9O4 [M+H] + :229.0523, found 229.0501.

[0173] Example 23

[0174] This embodiment provides a method for synthesizing urolithin b, which specifically includes the following steps:

[0175] At room temperature, a dibenzo-α-pyranone compound (2 mmol) of formula I was added to a 25 mL reaction flask equipped with a magnetic stirrer and dissolved in 10 mL of dichloromethane. Then, 3 mL of a 1 mol / L dichloromethane solution of boron tribromide was added, and the reaction was carried out at room temperature for 12 hours. After the reaction was completed, 10 mL of saturated sodium bicarbonate solution was added to the reaction solution, followed by extraction with dichloromethane (10 mL * 3 times). The organic phases were combined, concentrated by rotary evaporator, and the residue was purified by silica gel column chromatography to give 371 mg of urolithin b, with a yield of 87.5%.

[0176] like Figure 19 As shown, the obtained 1H NMR data for urolithin b are as follows:

[0177] 1 H NMR (600 MHz, DMSO) δ 10.37 (s, 1H), 8.24 (d, J = 6.9 Hz, 1H), 8.16 (dd, J = 14.6, 7.3 Hz, 2H), 7.87 (dd, J = 10.9, 7.3 Hz, 1H), 7.55 (td, J= 7.6, 3.1 Hz, 1H), 6.84 (d, J = 8.7 Hz, 1H), 6.75 (s, 1H).

[0178] like Figure 20 As shown, the obtained carbon NMR data for urolithin b are as follows:

[0179] 13 C NMR (151 MHz, DMSO) δ 160.64, 159.91, 152.14, 135.30, 135.12,129.70, 127.67, 124.86, 121.67, 118.96, 113.18, 109.38, 102.96.

[0180] The obtained high-resolution mass spectrometry data of urolithin b are: HRMS (ESI): m / z calcd. C 13 H9O3 [M+H] + :213.0542, found 213.0552.

[0181] Example 24

[0182] This embodiment provides a method for synthesizing urolithin C, which specifically includes the following steps:

[0183] At room temperature, a dibenzo-α-pyranone compound (2 mmol) of formula II was added to a 25 mL reaction flask equipped with a magnetic stirrer and dissolved in 10 mL of dichloromethane. Then, 3 mL of a 1 mol / L solution of boron tribromide in dichloromethane was added, and the reaction was carried out at room temperature for 12 hours. After the reaction was completed, 10 mL of saturated sodium bicarbonate solution was added to the reaction solution, followed by extraction with dichloromethane (10 mL * 3 times). The organic phases were combined, concentrated by rotary evaporator, and the residue was purified by silica gel column chromatography to give 268.4 mg of urolithin C, with a yield of 55.2%.

[0184] like Figure 21 As shown, the 1H NMR spectrum data of the obtained urolithin C are as follows:

[0185] 1 H NMR (600 MHz, DMSO) δ 10.15 (s, 3H), 7.85 (d, J = 8.8 Hz, 1H), 7.49 (s, 1H), 7.44 (s, 1H), 6.79 (dd, J = 8.7, 2.4 Hz, 1H), 6.69 (d, J = 2.4Hz, 1H).

[0186] like Figure 22 As shown, the obtained carbon NMR data for urolithin C are as follows:

[0187] 13 C NMR (151 MHz, DMSO) δ 160.35, 158.61, 153.49, 151.48, 146.16,129.21, 123.79, 114.19, 112.89, 110.87, 109.81, 106.88, 102.80.

[0188] The obtained high-resolution mass spectrometry data of urolithin C are: HRMS (ESI): m / z calcd. C 13 H9O5 [M+H] + :245.0461, found 245.0450.

[0189] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for synthesizing dibenzo-α-pyranone compounds, characterized in that, The process includes the following steps: using benzophenone compounds as raw materials, and reacting them with an oxidizing agent, a Lewis acid, and an oxidation catalyst in an organic solvent at room temperature; The benzophenone compounds have the structure shown in formula MI: MI, wherein R1, R2, R3 and R4 are each independently selected from H, halogen, C1-C6 alkyl or C1-C6 alkoxy; The oxidant is one of m-chloroperoxybenzoic acid, hydrogen peroxide, or tert-butyl hydrogen peroxide; The Lewis acid is one of zinc sulfide, aluminum trichloride, or ferric bromide; The oxidation catalyst is porphyrin ferric chloride.

2. The synthesis method according to claim 1, characterized in that, The molar amount of the oxidant is 1-10 times the molar amount of the benzophenone compound.

3. The synthesis method according to claim 2, characterized in that, The molar amount of the oxidant is 1-2 times the molar amount of the benzophenone compound.

4. The synthesis method according to claim 1, characterized in that, The molar amount of the Lewis acid is 0.05-0.5 times the molar amount of the benzophenone compound.

5. The synthesis method according to claim 4, characterized in that, The molar amount of the Lewis acid is 0.1-0.3 times the molar amount of the benzophenone compound.

6. The synthesis method according to claim 1, characterized in that, The molar amount of the oxidation catalyst is 0.05-0.5 times the molar amount of the benzophenone compound.

7. The synthesis method according to claim 6, characterized in that, The molar amount of the oxidation catalyst is 0.08-0.15 times the molar amount of the benzophenone compound.

8. The synthesis method according to claim 1, characterized in that, The organic solvent is tetrahydrofuran, dichloromethane, or hexafluoroisopropyl ether.

9. The synthesis method according to claim 8, characterized in that, The organic solvent is hexafluoroisopropyl ether.

10. The synthesis method according to any one of claims 1-8, characterized in that, The reaction time is 12-48 hours.

11. The synthesis method according to any one of claims 1-8, characterized in that, It also includes the following steps: washing, concentrating, and purifying the materials obtained from the reaction.

12. The application of the synthesis method according to any one of claims 1-11 in the synthesis of urolithin, characterized in that, The application method is as follows: Dibenzo-α-pyranone compounds are synthesized using the aforementioned synthesis method, and then urolithin is obtained by dealkylation reaction using the synthesized dibenzo-α-pyranone compounds as raw materials.

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